Originally posted by Nickishero:

it's your memory.
believe it or not, the error says so and my garry's mod uses even 5GB ram sometimes. (and still crashes like 1 time a month with that exact error)
try closing other applications
and prioritizing it higher in the taskbar.

Did this yesterday. Reinstalled GMod onto my SSD and gave it 4gb to work with. Can finally play now.

So I decided I wanted to play GMod again, only to find out that it was completely bugged. I therefore decided to unsubscribe and delete all of my addons and start over again. However when I decided to join this server, I kept crashing, only to be met by an Engine error.

http://prntscr.com/gutqfg

I've redownloaded GMod, Ive deleted all my addons. I've tried giving GMod more memory (4gb, currently at 2gb), I've downloaded the content pack. I've tried -heapsize and -dxlevel 98 and 90. I'm currently trying to run it in compatibility mode (Win 7).
Specs:
NVIDIA GeForce GTX960M
i7-6700HQ, 2,6GHz
8GB RAM
DDR4 Memory